The present invention generally relates to a safety switch assembly, and in particular to a safety switch of a type having a switch housing and a head portion attachable to an end face of the switch housing in several predetermined angular positions.
Safety switches of this type are known in many designs and are used for a wide range applications e.g. to cut the current supply when a protective cover is removed from an equipment or a machine or when equipment access doors and cabinet doors are opened. Such safety switches typically are formed with an access channel for entry of an actuator, e.g. a key, to operate the switch. The actuator may also be of a type secured to a flap, door, or lid at a predetermined distance to move together with the door, flap or the like. Common to all safety switches of this type is that they effect a shut-off when the actuator is withdrawn. The switch housing contains the switch, a plunger which operates the switch when moving in a longitudinal direction, and other suitable, electrical as well as electronic components. The head portion is attachable to the housing in different 90.degree. rotated dispositions and accommodates a mechanical switching element, e.g. a switch wheel or cam plate, which is operated by the actuator and interacts with a locking pin which retains the switch wheel in a locked position to prevent an unintended switch operation and is forcibly released by the actuator when being introduced in to the actuator channel.
Typically, the head portion is fastened by two screws to one end face of the housing so that conventional safety switches require a loosening of the screws, when re-adjusting the head portion with respect to the switch housing. Not only is this time consuming but there is the risk that screws get lost when making the required positional adjustments of the head portion. Moreover, as the switch housing is generally made of plastic material, the contact pressure applied by the screw fasteners is rather high in the adjoining region.